WASHINGTON — The United States imposed new sanctions Friday on Russia’s largest bank, a major arms maker and its biggest oil companies.

The sanctions, coordinated with similar European Union steps, were triggered by what the West sees as Moscow’s recent effort to destabilize eastern Ukraine by backing pro-Russia separatists with troops, heavy arms and cross-border shelling. They are the latest penalties imposed by the West since Russia annexed Crimea from Ukraine in March.

The sanctions target companies including Sberbank, Russia’s largest bank by assets, and Rostec, a conglomerate that makes everything from rifles to cars, by limiting their ability to access the US debt markets.

They also bar US companies from selling goods or services to five Russian energy companies to conduct deepwater, Arctic offshore and shale projects. The Russian firms affected are Gazprom, Gazprom Neft, Lukoil, Surgutneftegas and Rosneft.

The Obama administration stressed that the sanctions could be lifted if Russia — which denies sending troops into eastern Ukraine — took a series of steps, including the withdrawal of all of its forces from its besieged neighbor.

However, a defiant Russian President Vladimir Putin called the new penalties “strange.”

Russia’s Foreign Ministry said it would respond quickly with retaliatory measures against what it criticized as another “hostile step.”

The sanctions are not designed to curb Russia’s current, conventional oil production — but to hit future production by depriving Russian firms of the expertise of companies such as ExxonMobil and BP.